Grazed grass and silage are still among the cheapest feeds for cows. And steps can be taken to mitigate the cost of producing quality forage
TEXT PHIL EADES
With costs rising, the temptation might be to batten down the hatches this year, spend less and hope things improve next year. But Promar’s Garry Kidner says this could have significant financial repercussions, particularly when it comes to grassland management and feed costs next winter. “Even accounting for higher input costs and pricing 34% nitrogen at £650 per tonne, grass is still one of the most cost-effective feeds,” he stresses.
Grazed grass cost around £23/tDM in 2021 and, allowing for higher costs, this will be closer to £45/tDM in 2022. For a typical three-cut grass silage system the costs are £139/tDM, assuming all fieldwork is included at standard contractor charges.
“While accepting these increases are high, if producers opt out of growing sufficient good-quality forage they will be forced into increased purchased feed use,” he explains. “Based on Milkminder costings data, concentrates are currently averaging close to £320/tDM, and indications are that these prices are unlikely to weaken. Figures show that forage remains considerably cheaper, not forgetting that it is essential for efficient rumen function.”
Mr Kidner maintains that the two fundamental objectives to control feed costs and exploit increases in milk prices are to maximise contribution from forage, and to reduce the amount of purchased feeds used. But it will also be important for producers to take actions to reduce the impact of higher fertiliser and fuel prices. He says a high-quality grass sward will produce between 20kgDM and 30kgDM per kilogramme of nitrogen applied, although this response will decline at very high rates. “It will still pay to apply nitrogen, make sure it is applied effectively. Analyse soils and better match supply to requirements. Be prepared to vary application rates within fields and calibrate fertiliser spreaders to ensure this expensive input is going where it should.
Nutrient levels
“Make the best use of slurry too,” he adds. “Sample and test to determine nutrient levels. Split spring applications, totalling 67,000 litres per hectare of 6% dry matter slurry with a typical nitrogen content, will apply 60kgN/ha. “Typical ryegrass first-cut recommendations are to apply 120kgN/ha, meaning only 60kgN/ha of bagged nitrogen would be needed per hectare to meet requirements. This would cost £113/ha compared to £226/ha if all the nitrogen comes from the bag.”
He emphasises the need to use slurry carefully, as contaminating silage cuts can ruin fermentation and result in poor-quality forage. “Use a dribble bar or injection system to apply slurry close to the plant root.” Mr Kidner also urges producers to push ahead with reseeding plans, emphasising the higher productivity of new swards. “Replacing old leys can help improve both the quantity and quality of forage produced. By including a higher proportion of clover in seed mixtures, producers can also help future proof their unit by fixing atmospheric nitrogen and lowering the requirement for purchased nitrogen.”
Clover cover of between 20% and 30% can fix 180kgN/ ha per year – the equivalent to 521kg of a 34% nitrogen fertiliser – and will save £339/ha per year. Min- or no-till techniques, rather than ploughing, will minimise soil disturbance and erosion – and reduce costs. “Ploughing will use 3.5 times the diesel of double discing and 20 times the amount of fuel for a no tillage system.
“Producers should also reassess how they make grass silage. Are all the field operations necessary? “Also think about how many cuts to take. Question if multicut silage still has a place with higher fertiliser, fuel and contractor charges.”
Where producers have successfully managed to increase the energy and protein content of grass silage by cutting more often, Mr Kidner says they should continue. But he urges all who have been using the system to look closely at what they have achieved.
“What has actually happened to grass silage quantity and quality? Have they increased as much as expected, compared to a well-managed three-cut system? Has multi-cutting impacted on mid- and lateseason grazing availability?”
He predicts multicut systems will cost £179/tDM compared to £139/tDM for a three-cut system and, although quality will be higher overall, yield will be the same. The cost per cow will increase by around £200 and requires a significant concentrate saving to justify the added expense.
“But whatever system you use, focus on reducing waste at all stages of the process, which can be as high as 15% of all dry matter produced,” he adds. “Waste includes field losses due to excessive wilting and careless harvesting practices. Fermentation losses are more significant and go unseen. They are a consequence of slow filling, inadequate rolling, and clamp sealing.”
Reduce waste
Research shows using an effective additive will reduce dry matter losses by an average of 4%, and sometimes more. “Most observers would think it mad to throw away one in every 25 hectares harvested but this is what is happening, and it is avoidable at a low cost.
“Feed-out losses can also mount up. We see a lot of aerobic spoilage in clamps caused by grass ensiled when it is too dry, which results in overheating and a significant loss of dry matter. So always try to harvest below 35% dry matter,” says Mr Kidner.
“Ask how much waste are you prepared to tolerate when every kilogramme of silage dry matter you’ve made and can’t feed has to be replaced with more expensive purchased feeds? While reducing forage production should not be contemplated, I believe every dairy unit will be able to identify ways to increase cost-efficient production.”
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